Summer is well on its way, and you'll be hard-pressed to find a bistro in the region that doesn't have heirloom tomatoes on the menu. You'll find slices of chartreuse, amber, pink, vermilion, white, and brown tomatoes with knobs and stripes and hollow insides. But what exactly makes a tomato an heirloom?
According to food writer and farmer Gary Ibsen's TomatoFest website (www.tomatofest.com), heirloom tomatoes are open-pollinated varieties whose seeds were saved by families for generations or were sold commercially before hybridized varieties replaced them in the 1940s and '50s. A few of the "heirlooms" on the market come from more recent intentional or natural cross-pollination of older varieties.
When you spend $3 to $4 for a pound of heirloom tomatoes, you're not necessarily buying a delicate boutique fruit with lower yields and less resistance to disease. These varieties were passed down from generation to generation because they grew well and tasted great. What you're paying for is ripeness and freshness. Most commercial tomatoes are grown for uniform appearance and long shelf life. They're picked while green and are later ripened with ethylene gas, which is why they're colorless and flavorless.
Last week I swung through the Berkeley Farmers' Market looking for heirlooms. I brought home nine kinds to taste.
The greens -- especially tiny yellow-striped Zebras from Full Belly Farms -- had acidic, almost citrusy notes that would work well in salads. Riverdog Farms' "oxheart"-shaped Aunt Ruby's German tasted a little like a ripe green grape, and the brightness of Phillips Farm's Evergreens was tempered by their richness.
Though both the Gold Dust (lemon-yellow) and Golden Jubilees (sunflower-yellow) had intense skin-to-core color, they lacked distinction. But it's early in the season, which is probably why a normally rich Brandywine, pink and knobbly, was all juicy, bright fruit but hadn't developed depth. (In fact, the catch of the day was a crimson Early Girl, a hybrid from Riverdog Farms. Bred to ripen early, it was as tomatoey a tomato as you could find.)
I also picked up a couple of my favorites, the rich purples. Riverdog's small Black Princes were all earth and no sharp sweetness; Phillips' greenish Cherokee Purples almost matched the Early Girls for big flavor and packed in a heaping spoonful of sugar, too.
The best thing about organic heirloom tomatoes is that they're best left alone. Do what most of the swank restaurants do -- add a sprinkle of sea salt, a twist of the pepper mill, and splashes of fruity olive oil and balsamic vinegar. Suddenly, your $2 tomato will taste like an $8 appetizer, making heirlooms a bargain at twice the price.